Optical amplifier module housed in a factory cable joint

ABSTRACT

An optical amplifier module is provided that contains at least one optical amplifier. The module includes an internal housing having an outer dimension substantially equal to an outer dimension of an internal fiber splice housing of an undersea optical fiber factory cable joint. The internal housing includes a pair of opposing end faces each having a retaining element for retaining the internal housing within an outer housing of the undersea optical fiber cable joint. The internal housing also includes a sidewall interconnecting the opposing end faces, which extends between the opposing end faces in a longitudinal direction. The sidewall includes a receptacle portion having a plurality of thru-holes each being sized to receive a passive optical component employed in an optical amplifier. The module also includes at least one circuit board on which reside electronics associated with the optical amplifier. An isolated electrical path provides electrical power received from a conductor in at least one optical fiber cable to the at least one circuit board.

STATEMENT OF RELATED APPLICATION

This application is a continuation-in-part and claims the benefit ofpriority of co-pending U.S. patent application Ser. No. 10/715,330,filed Nov. 17, 2003, entitled “Method and Apparatus For ElectricallyIsolating An Optical Amplifier Module Housed In A Universal CableJoint,” which claims the benefit of priority to U.S. Provisional PatentApplication 60/433,189, filed Dec. 13, 2002, entitled “Method AndApparatus For Electrically Isolating An Optical Amplifier Module HousedIn A Universal Cable Joint.” Both of these prior applications areincorporated herein by reference in their entireties.

FIELD OF THE INVENTION

The present invention relates to the field of optical repeaters, andmore particularly to an optical repeater employed in an undersea opticaltransmission system.

BACKGROUND OF THE INVENTION

In undersea optical transmission systems optical signals that aretransmitted through an optical fiber cable become attenuated over thelength of the cable, which may span thousands of miles. To compensatefor this signal attenuation, optical repeaters are strategicallypositioned along the length of the cable.

In a typical optical repeater, the optical fiber cable carrying theoptical signal enters the repeater and is coupled through at least oneamplifier and various components, such as optical couplers anddecouplers, before exiting the repeater. These optical components arecoupled to one another via optical fibers. Repeaters are housed in asealed structure that protects the repeaters from environmental damage.During the process of deployment, the optical fiber cable is coiled ontolarge drums located on a ship. Consequently, the repeaters becomewrapped about the drums along with the cable. Due to the nature of thesignals, and the ever increasing amount of information being transmittedin the optical fibers, repeaters are getting larger, and their increasedlength creates problems as they are coiled around a drum. Although thedrums may be up to 9-12 feet in diameter, current repeaters may begreater than 5 feet in length, and, therefore, are not able to lie flat,or even substantially flat, along a drum. Tremendous stresses due toforces on the order of up to 100,000 pounds are encountered at theconnection point between the repeater and the fiber optic cable to whichit is attached, especially during paying out and reeling in of thecable. The non equi-axial loading across the cable may arise as a resultof severe local bending that is imposed on the cable at its terminationwith the repeater. This loading would inevitably lead to failure ofcable components at loads well below the tensile strength of the cableitself.

To prevent failure of the cable during deployment of the repeater, abend limiter is often provided, whose purpose is to equalize the forcesimposed on the cable. In addition, a gimbal may be provided at eachlongitudinal end of the repeater to which the bend limiting devices areattached. The gimbal provides free angular movement in two directions.The bend angle allowed by the gimbal between the repeater and bendlimiting device further reduces the local bending that is imposed on theoptical fiber cables.

The large physical size of conventional repeaters increases theircomplexity and cost while creating difficulties in their deployment.

SUMMARY OF THE INVENTION

In accordance with the present invention, an optical amplifier module isprovided that contains at least one optical amplifier. The moduleincludes an internal housing having an outer dimension substantiallyequal to an outer dimension of an internal fiber splice housing of anundersea optical fiber cable joint. The internal housing includes a pairof opposing end faces each having a retaining element for retaining theinternal housing within an outer housing of the undersea optical fibercable joint. The internal housing also includes a sidewallinterconnecting the opposing end faces, which extends between theopposing end faces in a longitudinal direction. The sidewall includes areceptacle portion having a plurality of thru-holes each being sized toreceive a passive optical component employed in an optical amplifier.The module also includes at least one circuit board on which resideelectronics associated with the optical amplifier. An isolatedelectrical path provides electrical power received from a conductor inat least one optical fiber cable to the at least one circuit board.

In accordance with one aspect of the invention, the undersea opticalfiber cable joint includes a pair of cable termination units in whichend portions of optical fiber cables to be jointed are respectivelyretained. The retaining elements are each connectable to one of thecable termination units.

In accordance with another aspect of the invention, the conductor ofeach of the optical fiber cables to be jointed are in electrical contactwith one of the retaining elements.

In accordance with another aspect of the invention, the isolatedelectrical path includes a power conductor located within the circuitboard that is in electrical contact with one of the retaining elements.

In accordance with another aspect of the invention at least one voltagedropping element is provided for conveying a portion of voltage from thepower conductor to the electronics associated with the opticalamplifier.

In accordance with another aspect of the invention, the voltage droppingelement is a zener diode.

In accordance with another aspect of the invention, the circuit boardcomprises a pair of circuit boards, and the isolated electrical pathfurther includes at least one electrically conductive pin electricallyconnecting the power conductors of the pair of circuit boards.

In accordance with another aspect of the invention, the plurality ofthru-holes laterally extend through the receptacle portion of thesidewall in the longitudinal direction.

In accordance with another aspect of the invention, the internal housinghas a generally cylindrical shape. The receptacle portion of thesidewall has a curvature that defines a diameter of the cylindricalshape.

In accordance with another aspect of the invention, the undersea opticalfiber cable joint is a universal joint for jointing optical cableshaving different configurations.

In accordance with another aspect of the invention, the universal jointincludes a pair of cable termination units in which end portions of theoptical cables to be jointed are respectively retained. The retainingelements are each connectable to one of the cable termination units.

In accordance with another aspect of the invention, the retainingelements each include a flange through which at least one optical fiberextending from the end portion of one of the optical cables extends intothe internal housing.

In accordance with another aspect of the invention, the optical fiberstorage area includes at least one optical fiber spool around whichoptical fiber can be wound.

In accordance with another aspect of the invention, the internal housingis formed from a pair of half units that each include one of theretaining elements.

In accordance with another aspect of the invention, the sidewallincludes a pair of ribbed members extending longitudinally from thereceptacle portion of the sidewall. The ribbed members each have atension rod thru-hole extending laterally therethrough in thelongitudinal direction for supporting a tension rod employed by theundersea optical fiber cable joint.

In accordance with another aspect of the invention, the outer dimensionof the internal housing is less than about 15 cm×50 cm.

In accordance with another aspect of the invention, the outer dimensionof the internal housing is about 7.5 cm×15 cm.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example of an undersea optical fiber cable.

FIG. 2 shows a simplified schematic diagram of a universal cable jointfor jointing fiber optic cables for use in undersea opticaltelecommunication systems.

FIG. 3 shows a particular example of a universal cable joint that isavailable from Global Marine Systems Limited and the Universal JointConsortium.

FIG. 4 shows a side view of an optical amplifier module constructed inaccordance with the present invention.

FIG. 5 shows a perspective view of one of the half units that form theoptical amplifier module depicted in FIG. 4.

FIG. 6 shows a side view of one of the half units that form the opticalamplifier module depicted in FIG. 4.

FIG. 7 shows a cross-sectional side view one of the half units that formthe optical amplifier module depicted in FIG. 4.

FIG. 8 is cross-sectional side view of the optical amplifier moduleshown in FIG. 4.

FIG. 9 is an enlarged, cross-sectional side view of the portion of theoptical amplifier module that interconnects with the end cap.

DETAILED DESCRIPTION

The present inventors have recognized that a substantially smallerrepeater can be achieved by first reducing the length of the repeater sothat the stresses placed upon it during its deployment are greatlyreduced, thereby eliminating the need for gimbals. The elimination ofthe gimbals, in turn, allows further reductions in the dimensions of therepeaters.

The present inventors have further recognized that a repeatersubstantially reduced in size can be housed in a unit formed fromoff-the-shelf components that have been qualified for the underseaenvironment. In particular, the inventors have recognized that a housingconventionally used for interconnecting different undersea optical fibercables can also be used as an ultra-small form-factor repeater housing.As discussed below, one such housing, commonly referred to as theUniversal Joint, has become the defacto worldwide standard formaintaining submarine cables and has a lengthy history of successfuldeployment. The present invention thus provides a repeater that, becauseof its small size, is easily deployed and which is located in aneconomical, submarine qualified housing that is already well establishedin the undersea optical communications industry. Moreover, because theUniversal Joint can interconnect different optical fiber cables, therepeater can be used to interface with a variety of cables and systemsfrom different manufacturers.

To facilitate an understanding of the present invention, an example ofan undersea optical fiber cable will be described in connection withFIG. 1. While different cable manufactures employ cables havingdifferent configurations and dimensions, most cables employ most of thecomponents depicted in FIG. 1 in one form or the other. Optical cable330 comprises a single, centrally located gel-filled buffer tube 332made from a metal such as aluminum or stainless steel. The gel-filledbuffer tube 332 contains optical fibers 335. In some cases the buffertube 332 is replaced with a centrally disposed kingwire that issurrounded by optical fibers that are embedded in a polymer. Two layersof strandwires, which serve as strength members, are wound around thebuffer tube. One layer includes strandwires 338 and the other layerincludes strandwires 339. A copper conductor 340 surrounds thestrandwires and serves as both an electrical conductor and a hermeticbarrier. An outer jacket 342 formed from polyethylene encapsulates thecopper conductor 340 and serves as an insulating layer.

FIG. 2 shows a simplified schematic diagram of a universal cable jointfor jointing fiber optic cables for use in undersea opticaltelecommunication systems. Such a joint is referred to as a universalcable joint because it can interconnect many different types of underseaoptical telecommunication cables, regardless of manufacturer. The cablejoint includes a common component assembly 10 in which an optical fibersplice is located. The fiber splice is formed from two fibers thatrespectively originate in two cables that each terminate in cabletermination units 12. A protective assembly 15 surrounds commoncomponent assembly 10 and cable termination units 12 to provideprotection from the external environment.

FIG. 3 shows a particular example of a universal cable joint that isavailable from Global Marine Systems Limited and the Universal JointConsortium, which, as previously mentioned, is often simply referred toas the Universal Joint. In FIGS. 2 and 3, as well as the figures thatfollow, like reference numerals indicate like elements. In FIG. 3, theprotective assembly 15 depicted in FIG. 2 comprises a stainless steelsleeve 14 that surrounds the common component assembly 10 and apolyethylene sleeve 16 that is molded over the common component assembly10. The stainless steel sleeve 14 provides resistance to tensile,torsional and compressive loads and further provides an electricallyconductive path through which electrical power can be transmitted fromthe copper conductor of one cable to the copper conductor of the other.

The jointing process begins by stripping back the various layers of thecable to reveal predetermined lengths of the outer jacket, copperconductor, strandwires, and the fiber package (e.g., the buffer tubecontaining the optical fibers or the kingwire surrounded by the opticalfibers). The strandwires are clamped in a ferrule assembly located inthe cable termination units 12. The fiber package extends into thecommon component assembly 10, where it is held in place by a series ofclamps. In the common component assembly 10 the individual fibers areseparated and spliced to their corresponding fibers from the othercable. The splices, along with excess fiber, are looped and wound inchannels that are formed within the common component assembly 10. Thecommon component assembly 10 is inserted in the stainless steel sleeve14 and end caps 13 are screwed to each end of the assembly 10. Twotension rods 17 and 19 extend through the end caps 13 and the commoncomponent assembly 10. The tension rods 17 and 19 are designed to carrythe tension loads that are placed on the universal joint during thedeployment process as the joint is transferred from a ship to itsundersea environment. Finally, the joint is laid in a mold that isinjected with molten polyethylene to provide an insulate (i.e.,polyethylene sleeve 16) that is continuous with the outer jacket of thecables.

Universal cable joints such as the aforementioned Universal Jointavailable from Global Marine Systems Limited and the Universal JointConsortium, which interconnect many different types of undersea opticaltelecommunication cables, regardless of manufacturer, are primarilydesigned for repair of an existing undersea transmission cable. Inaddition to universal cable joints, the present invention may alsoemploy a factory cable joint that is used to joint submarine cablesduring their initial installation. Factory cable joints, which areavailable from most submarine cable manufacturers, are generallymanufacturer-specific and thus can only accommodate an undersea cabletype or types from a given manufacturer. For example, one factory cablejoint that may be employed is model NCD-601 available from EricssonNetwork Technologies. Of course, such factory cable joints are currentlyavailable from numerous other manufacturers as well.

The present inventors have recognized that a cable joint such as theuniversal cable joints depicted in FIGS. 2-3 or a factory cable jointcan be modified to serve as a repeater housing in which 1 or moreoptical amplifiers are located. FIGS. 4-9 show one embodiment of anoptical amplifier module 400 that replaces the common component assembly10 seen in FIGS. 1-4. The optical amplifier module 400 must havesubstantially the same dimensions as the common component assembly,which is only about 7.5 cm×15 cm. As previously mentioned, this is farless in size than conventional repeater housings, which are oftenseveral feet in length. The optical amplifier module 400 depicted in thefigures can support 4 erbium-doped fiber amplifiers (EDFAs), physicallygrouped as a dual amplifier unit for each of two fiber pairs. Of course,the present invention encompasses optical amplifier modules that cansupport any number EDFAs.

Each optical amplifier includes an erbium doped fiber, an optical pumpsource, an isolator and a gain flattening filter (GFF). The amplifiersare single-stage, forward pumped with cross-coupled pump lasers. A 3 dBcoupler allows both coils of erbium doped fiber in the dual amplifier tobe pumped if one of the two pump lasers fails. At the output, anisolator protects against backward-scattered light entering theamplifier. The gain flattening filter is designed to flatten theamplifier gain at the designed input power. An additional optical pathmay be provided to allow a filtered portion of the backscattered lightin either fiber to be coupled back into the opposite direction, allowingfor COTDR-type line-monitoring. Of course, optical amplifier module 400may support EDFAs having different configurations such as multistageamplifiers, forward and counter-pumped amplifiers, as well as fiberamplifiers that employ rare-earth elements other than erbium.

The optical amplifier module 400 is designed to be compatible with theremainder of the cable joint so that it connects to the cabletermination units 12 and fits within the stainless steel sleeve 14 inthe same manner as the common component assembly 10.

A side view of optical amplifier module 400 is shown in FIG. 4 with endcaps 13 in place. The module 400 is defined by a generally cylindricalstructure having flanges 402 (seen in FIG. 5) located on opposing endfaces 403. A longitudinal plane 405 extends through the opticalamplifier module 400 to thereby bisect the module 400 into two halfunits 404 and 404′ that are symmetric about a rotational axisperpendicular to the longitudinal plane 405. That is, as best seen inFIG. 5, rather than dividing the end faces 403 into two portions locatedon different half units 404, each half unit 404 includes the portion ofone of the end faces 403 on which a respective flange 402 is located.FIG. 5 shows a perspective view of one of the units 404. In theembodiment of the invention depicted in FIGS. 4-9, each half unit 404houses two erbium-doped fiber amplifiers

Flanges 402 mate with the cable termination units 12 of the UniversalJoint shown in FIG. 3. As seen in the cross-sectional views of FIGS. 7and 8, through-holes 407 extend inward from the end faces 403 throughwhich the tension rod of the universal joint are inserted. The end faces403 also include clearance holes 430 for securing the end caps 13 of theUniversal Joint to the optical amplifier module 400. The clearance holes430 are situated along a line perpendicular to the line connecting thetension rods thru-holes 407.

As shown in FIGS. 4-6, each unit 404 includes curved sidewalls 412forming a half cylinder that defines a portion of the cylindricalstructure. A spinal member 406 is integral with and tangent to thecurved sidewalls 412 and extends longitudinally therefrom. The thru hole407 containing the tension rod of the universal joint extends throughthe spinal member 406. A ceramic boss 440 is located on the end of thespinal member 406 remote from the end flange 403. As shown in FIGS. 5and 7, the thru hole 407 extends through the ceramic boss 440. Asdiscussed below, the ceramic boss 440 prevents the flow of current fromone half unit 404 to the other.

A circuit board support surface 416 extends along the periphery of theunit 404 in the longitudinal plane 405. Circuit board 426 is mounted onsupport surface 416. When the half units 404 and 404′ are assembled,circuit boards 426 and 426′ are interconnected by a pair of interlockingconductive power pins 423 that provide electrical connectivity betweenthe two circuit boards 426 and 426′. The inner cavity of the unit 404located between the circuit board support surface 416 and the spinalmember 406 serves as an optical fiber storage area. Optical fiber spools420 are located on the inner surface of the spinal member 406 in theoptical fiber storage area. The erbium doped fibers, as well as anyexcess fiber, are spooled around the optical fiber spools 420. Theoptical fiber spools 420 have outer diameters that are at least greatenough to prevent the fibers from bending beyond their minimum specifiedbending radius.

The curved sidewalls 412 are sufficiently thick to support a pluralityof thru-holes 418 that extend therethrough in the longitudinaldirection. The thru-holes 418 serve as receptacles for the passivecomponents of the optical amplifiers. That is, each receptacle 418 cancontain a component such as an isolator, gain flattening filter, couplerand the like.

End faces 403 each include a pair of pump support bosses 403 a (seeFIGS. 6 and 7) that extend inward and parallel to the circuit board 426.The circuit board 426 has cut-outs so that the pump support bosses 403 aare exposed. A pump source 427 that provides the pump energy for eachoptical amplifier is mounted on each pump boss 403 a.

Electrical Connectivity

As previously mentioned, electrical connectivity must be maintainedbetween the cables in the two cable termination units 12. However, thevarious components in the optical amplifier module 400 must beelectrically isolated to enable a small voltage (e.g., 5-20 v) that mustbe supplied to the electrical components located on the circuit boards426.

Referring again to FIG. 3, the optical amplifier module 400 and sleeve14 are surrounded by polyethylene sleeve 16, which serves as adielectric. Electrical power is taken from the conductor in the cablelocated in the termination units 12 and transferred through a conductorlocated in the circuit board 426. The circuit board is electricallyisolated from the optical amplifier module 400, with the epoxy resin ofthe circuit board acting as a local dielectric. After the voltage isdropped to the electrical components on one of the circuit boards thevoltage is passed from circuit board 426 to circuit board 426′ via apair of complaint conductive pins 423 that each comprise a pin andsocket assembly. The pins 423 allow for any axial movement that mayoccur as a result of tension or hydrostatic pressure.

More specifically, with reference now to FIGS. 7 and 8, power issupplied to the electrical components as follows. Since the cabletermination units 12 are electrically powered or active, end caps 13 arealso electrically active. A power conductor extends within each of thecircuit boards 426 and 426′. The power conductors receive electricalpower directly from the pump support bosses 403 a. One or more voltagedropping elements such as zener diodes are located on the circuit board426. The zener diodes, which electrically couple the power conductors tothe other electrical components on the circuit board, drop a voltagethat is sufficient to power the electrical components. Electricconnectivity extends along the power conductors and is maintained acrossthe circuit boards to the other via the conductive pins 423. In this wayelectric conductivity extends from one end cap 13, through the endflange 403 and pump support boss 403 a in contact with the end cap 13,through the power conductor located on the circuit board 426 resting onthe pump support boss 403 a, through one of the power pins 423 andthrough the power conductor located in the other circuit board 426.Finally, electrical conductivity extends to the other end cap 13 via theother pump support boss 403 a and end flange 403.

The electrical path is isolated from the optical amplifier module 400 asfollows. A thermal and electrically insulating pad is located betweenthe circuit board support surface 416 and the circuit board 426. In thisway the pump support boss 403 a is electrically isolated from thecircuit board 426, except through the aforementioned power conductor.Ceramic isolators 442 surround the bolts that secure the circuit board426 to the sidewalls 412 of each half unit 404. The ceramic isolators442 prevent electrical discharges from the bolts to the componentslocated on the circuit board 426. The ceramic boss 440 located on eachhalf unit 404 electrically isolates the spinal member 406 to which it isconnected from both the end cap 13 and the end flange 403 with which itis in contact.

FIG. 9 shows the manner in which the tension rods 409 extending throughthru-holes 407 are electrically isolated from the end caps 13. As shownin FIG. 9 for the left-most end cap 13, a ceramic washer 444 surroundsthe head of each tension rod 409. The ceramic washer 444 electricallyisolates the end cap 13 from the tension rod 409. Because the sealestablished by the ceramic washer 444 is not hermetic, copper washers446 and 448 are also provided to ensure that such a hermetic seal isachieved between the tension rod and the end cap 13. The threaded end ofthe tension rods 409 terminate in the opposing end cap 13 and thethreaded ends are not electrically isolated from the end cap 13.

Since the sleeve 14 contacts the end caps 13, sleeve 14 shouldpreferably be formed from a non-conductive material. For example, sleeve14 may be formed from a thermally conductive ceramic, which isadvantageous because of its strength. However, because such ceramics areoften nominally electrically conductive they need to be provided with anoxide surface in order serve as a dielectric. The surface finish of theoxide is preferably polished to facilitate formation of a hermetic seal.

1. An optical amplifier module containing at least one opticalamplifier, said module comprising: an internal housing having an outerdimension substantially equal to an outer dimension of an internal fibersplice housing of an undersea optical fiber factory cable joint, saidinternal housing including: a pair of opposing end faces each having aretaining element for retaining the internal housing within an outerhousing of said undersea optical fiber factory cable joint; a sidewallinterconnecting said opposing end faces and extending between saidopposing end faces in a longitudinal direction, said sidewall includinga receptacle portion having a plurality of thru-holes each being sizedto receive a passive optical component employed in an optical amplifier;at least one circuit board on which reside electronics associated withthe optical amplifier; and an isolated electrical path for providingelectrical power received from a conductor in at least one optical fibercable to the at least one circuit board.
 2. The optical amplifier moduleof claim 1 wherein said undersea optical fiber cable joint includes apair of cable termination units in which end portions of optical fibercables to be jointed are respectively retained, said retaining elementseach being connectable to one of the cable termination units.
 3. Theoptical amplifier module of claim 2 wherein said conductor of each ofthe optical fiber cables to be jointed are in electrical contact withone of the retaining elements.
 4. The optical amplifier module of claim3 wherein said isolated electrical path includes a power conductorlocated within the circuit board that is in electrical contact with oneof the retaining elements.
 5. The optical amplifier module of claim 4further comprising at least one voltage dropping element for conveying aportion of voltage from the power conductor to the electronicsassociated with the optical amplifier.
 6. The optical amplifier moduleof claim 5 wherein said voltage dropping element is a zener diode. 7.The optical amplifier module of claim 4 wherein said at least onecircuit board comprises a pair of circuit boards, and wherein saidisolated electrical path further comprises at least one electricallyconductive pin electrically connecting the power conductors of the pairof circuit boards.
 8. The optical amplifier module of claim 1 whereinsaid plurality of thru-holes laterally extend through said receptacleportion of the sidewall in the longitudinal direction.
 9. The opticalamplifier module of claim 1 wherein said internal housing has agenerally cylindrical shape, said receptacle portion of the sidewallhaving a curvature that defines a diameter of the cylindrical shape. 10.The optical amplifier module of claim 1 wherein the undersea opticalfiber cable joint is a universal joint for jointing optical cableshaving different configurations.
 11. The optical amplifier module ofclaim 1 wherein said retaining elements each include a flange throughwhich at least one optical fiber extending from the end portion of oneof the optical cables extends into the internal housing.
 12. The opticalamplifier module of claim 1 flintier comprising an optical fiber storagearea located within said internal housing.
 13. The optical amplifiermodule of claim 12 wherein said optical fiber storage area includes atleast one optical fiber spool around which optical fiber can be wound.14. The optical amplifier nodule of claim 1 wherein said internalhousing is formed from a pair of half units that each include one of theretaining elements.
 15. The optical amplifier module of claim 7 whereinsaid internal housing is formed from a pair of half units that eachinclude one of the retaining elements.
 16. The optical amplifier moduleof claim 15 wherein each circuit board is located in a different one ofthe half units
 17. The optical amplifier module of claim 1 wherein saidsidewall includes a pair of ribbed members extending longitudinally fromthe receptacle portion of the sidewall, said ribbed members each havinga tension rod thru-hole extending laterally therethrough in thelongitudinal direction for supporting a tension rod employed by theundersea optical fiber cable joint
 18. The optical amplifier module ofclaim 1 wherein the outer dimension of the internal housing is less thanabout 15 cm×50 cm.
 19. The optical amplifier module of claim 1 whereinthe outer dimension of the internal housing is about 7.5 cm×15 cm.20-39. (canceled)
 40. An undersea optical repeater, comprising: anexternal, hermetically sealed outer housing of an undersea optical fiberfactory cable join an optical amplifier module comprising: a protectivesleeve located in said outer housing; an internal housing located insaid protective sleeve, said internal housing including: a pair ofopposing end faces each having a retaining element for retaining theinternal housing within an outer housing of said undersea optical fiberfactory cable joint; and a sidewall interconnecting said opposing endfaces and extending between said opposing end faces in a longitudinaldirection, said sidewall including a receptacle portion having aplurality of thru-holes each being sized to receive a passive opticalcomponent employed in an optical amplifier; at least one circuit boardon which reside electronics associated with the optical amplifier; andan isolated electrical path for providing electrical power received froma conductor in a pair of optical fiber cables to the at lean one circuitboard.
 41. The undersea optical repeater of claim 40 further comprisinga pair of cable termination units in which end portions of the opticalfiber cables to be jointed are respectively retained, said retainingelements each being connected to one of the cable termination units. 42.The undersea optical repeater of claim 40 wherein said conductor of eachof the optical fiber cables to be jointed are in electrical contact withone of the retaining elements.
 43. The undersea optical repeater ofclaim 41 wherein said conductor of each of the optical fiber cables tobe jointed are in electrical contact with one of the retaining elements.44. The undersea optical repeater of claim 42 wherein said isolatedelectrical path includes a power conductor located within the circuitboard that is in electrical contact with one of the retaining elements.45. The undersea optical repeater of claim 44 further comprising atleast one voltage dropping element for conveying a portion of voltagefrom the power conductor to the electronics associated with the opticalamplifier.
 46. The undersea optical repeater of claim 45 wherein saidvoltage dropping element is a zener diode.
 47. The undersea opticalrepeater of claim 40 wherein said at least one circuit board comprises apair of circuit boards, and wherein said electrical path furthercomprises at least one electrically conductive pin electricallyconnecting the power conductors of the pair of circuit boards.
 48. Theundersea optical repeater of claim 40 wherein said plurality ofthru-holes laterally extend through said receptacle portion of thesidewall in the longitudinal direction.
 49. The undersea opticalrepeater of claim 40 wherein said internal housing has a generallycylindrical shape, said receptacle portion of the sidewall having acurvature that defines a diameter of the cylindrical shape.
 50. Theundersea optical repeater of claim 40 wherein the undersea optical fibercable joint is a universal joint for jointing optical cables havingdifferent configurations.
 51. The undersea optical repeater of claim 40wherein said retaining elements each include a flange through which atleast one optical fiber extending from the end portion of one of theoptical fiber cables extends into the internal housing.
 52. The underseaoptical repeater of claim 40 further comprising an optical fiber storagearea located within said internal housing.
 53. The undersea opticalrepeater of claim 52 wherein said optical fiber storage area includes atleast one optical fiber spool around which optical fiber can be wound.54. The undersea optical repeater of claim 40 wherein said sidewallincludes a pair of ribbed members extending longitudinally from thereceptacle portion of the sidewall, said ribbed members each having atension rod thru-hole extending laterally therethrough in thelongitudinal direction and further comprising a tension rod extendingthrough one of the tension rod thru-holes and each of the end faces. 55.The undersea optical repeater of claim 54 wherein the tension rods areeach electrically isolated from at least one of the end faces.
 56. Theundersea optical repeater of claim 40 wherein the outer dimension of theinternal housing is less than about 15 cm×50 cm.
 57. The underseaoptical repeater of claim 40 wherein the outer dimension of the internalhousing is about 7.5 cm×15 cm.
 58. An optical amplifier modulecontaining at least one optical amplifier, said module comprising: aninternal housing having an outer dimension substantially equal to anouter dimension of an internal fiber splice housing of an underseaoptical fiber cable joint, said internal housing including: a pair ofopposing end faces each having a staining element for retaining theinternal housing within an outer housing of said undersea optical fibercable joint; a sidewall interconnecting said opposing end faces andextending between said opposing end faces in a longitudinal direction,said sidewall including a receptacle portion having a plurality ofreceiving elements each being sized to receive a passive opticalcomponent employed in an optical amplifier; at least one circuit boardon which reside electronics associated with the optical amplifier; andan isolated electrical path for providing electrical power received froma conductor in at least one optical fiber cable to the at least onecircuit board.
 59. An undersea optical repeater, comprising: anexternal, hermetically sealed outer housing of an undersea optical fibercable joint, an optical amplifier module comprising: a protective sleevelocated in said outer housing; an internal housing located in saidprotective sleeve, said internal housing including: a pair of opposingend faces each having a raining element for retaining the internalhousing within the outer housing of said undersea optical fiber cablejoint; and a sidewall interconnecting said opposing end faces andextending between said opposing end aces in a longitudinal direction,said sidewall including a receptacle portion having a plurality ofreceiving elements each being sized to receive a passive opticalcomponent employed in an optical amplifier, at least one circuit boardon which reside electronics associated with the optical amplifier; andan isolated electrical path for providing electrical power received froma conductor in a pair of optical fiber cables to the at least onecircuit board.